Technical Field
The present invention relates to a power bank device, especially to a power bank device and current-output method thereof.
Related Art
An increasing variety of electric portable devices has been developed due to the progress of technology. Accordingly, it is common to carry one or more electric products. Existing portable electric devices, such as mobile phones, laptop computers, digital cameras, MP3s, etc., use rechargeable batteries as the power source. Traditionally, users may need to use an equipped charger (transformer), to charge their electric device by changing the AC power supply to a specific voltage level. However, when the environment of AC power supply is unknown, the portable device may be unchargeable or unusable. Consequently, the power bank device with a rechargeable battery has been developed to provide the electric device with power supplied by the power bank device.
However, the specification of different electric devices may be different. For example, the required charging current is one ampere for a smart phone, but a Pad computer needs two amperes. The power bank device may be set with a different capacity and output power; that is the setting may be based on an output current of one or two amperes. However, when the output power of the power bank device is higher, the size of the power bank device is relatively larger. This may be inconvenient for users to carry. With respect to the above problems, there is a need for solution to the existing problems.